Evidence for σ → η 3 rearrangement reaction in gaseous ions from Fe, Mn and Re allylic derivatives

Abstract

The fragmentation pathways of (η 3-C 3H 4X)FeCO) 2NO, (σ-C 3H 4X)Fe(CO) 2(NO)L, (η 3-C 3H 4X)Fe(CO)(NO)L, (σ-C 3H 4X)Fe(CO) 2(NO)L′, (η 3- C 3H 4X)Fe(CO)(NO)L′, (σ-C 3H 5)M(CO) 5, (η 3-C 3H 5)M(CO) 4, (σ-CH 2CHC(Me) 2)Mn(CO) 5, (η 3-CH 2 CHC(Me) 2)Mn(CO) 4, (X=2-Cl; L=PPh 3; L′= P(OMe) 3; M=Mn, Re) have been investigated by mass spectrometry. In the σ derivatives the molecular ion loses CO or the allylic ligand, while in the η 3 derivative loss of a CO group is the only fragmentation mode of the molecular ion. Electron impact as well as methane chemical ionization mass spectra have been reported. Kinetic energy release of selected metastable ions indicates that a σ → η 3 rearrangement reaction occurs.